PTL 1 discloses a railcar bogie configured such that: side sills are omitted from a bogie frame; and a plate spring achieves the function of a side sill and the function of a primary suspension. The plate spring includes a fiber-reinforced resin upper surface member, a fiber-reinforced resin lower surface member, and a core material member arranged between the upper surface member and the lower surface member, and these members are bonded to one another.